This is all done with impression as opposed to cutting.
Just one piece of scrap 3mm. Foamex, pushed into different levels and impressed with the back of a graver.
The brickwork was first pushed slightly lower than the render and then impressed with the back of a craft knife, with the upper courses done with the edge of the knife, just pushed down, not drawn along...take your pick.
The render was then pressed with a new sheet of 80 grit emery cloth to give it more texture, although some texture is on the Foamex as standard.
The door and its frame were also pressed to slightly different levels, before being impressed with planking detail.
Finally, to make a corner to the building, the back has been cut away with a V to within an ace of the surface and then the corner merely bent in, but a mitred corner would be fine if you go through.
The back of this piece of Foamex shows that my samples came from a signage company!